Clouds in Space

Voyager makes an interstellar discovery   PhysOrg - December 27, 2009
The solar system is passing through an interstellar cloud that physics says should not exist.

Molecular Cloud Barnard 68 NASA March 23, 2008

Where did all the stars go? What used to be considered a hole in the sky is now known to astronomers as a dark molecular cloud.

Scientists discover vast intergalactic plasma cloud PhysOrg - April 20, 2007

Sugar Found in Frigid Space Cloud

Discovery - September 2004

Astronomers have found a sweet spot in a sublimely cold and vast interstellar cloud. An eight-atom called glycolaldehyde has been found residing at eight degrees above absolute zero in the Sagittarius B2 dust cloud, some 26,000 light-years from Earth. The sugar is just a few steps from ribose, an essential ingredient of DNA.

"This is a very cold cloud," said astronomer Philip Jewell of the National Radio Astronomy Observatory and part of the discovery team. "It's too cold for (the sugar) to have formed in that environment." Some sort of additional energy was needed to throw simpler molecules together to make the sugar, he said. What probably provided the sugar-making oomph was a shock wave from an exploding star, said Jewell. A shock wave would heat up pre-existing simpler molecules — water, ammonia, formaldehyde, methane, ammonia or carbon dioxide — so they could react and build the sugar. Once the reactions occurred, the molecules dispersed and cooled. The simpler molecules are thought to form on the surfaces of dust particles.

This is the second detection of glycolaldehyde in space, said Jewell, the first being in 2000, but a much warmer sugar, less revealing and a weaker signal. The glycolaldehyde was found using the Robert C. Byrd Green Bank Telescope in West Virginia to detect a radio signal emitted at a narrow and precise frequency when the sugar molecules rotate. The team's results appeared in the Sept. 20 issue of Astrophysical Journal Letters.

"This sugar is a relatively complex molecule," said astronomy professor Edward Churchwell of the University of Wisconsin in Madison. "The whole issue of complex molecules in interstellar space was thought in the 1970s to be impossible." It was thought impossible because space between stars in our galaxy is rife with various forms of radiation that tend to knock apart large clumps of atoms.

Today astronomers know that the gigantic dust and gas clouds within the Milky Way provide shelter from radiation for molecules. "There are regions in space that are protected from all this radiation," Churchwell said.

The discovery hints of a rich molecular soup floating in the clouds between stars, said Churchwell, in the very places where they are most likely to find their way onto new planets. Clouds like Sagittarius B2 are where stars, and their planets, are born, he said.